Enclosure not stated
Sallen Key 2P Filters
- Category
- Other· Filters Wahs and VCFs
- Price
- see vendor
- Tags
- Filters Wahs and VCFs
Schematic
The schematic is the archived file. Open it at Experimentalists Anonymous, or browse its folder.
Parts list 25 rows
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Check before you build · 4 values the reader of this schematic was not sure of
- 0.1uF: printed '01µF', could be .01uF
- input electrolytic value illegible
- Q1-Q3 handwritten substitutes read BC547 (Q2's could be BC517)
- 1k count: one resistor label under C2 reads '1k' faintly
| Ref | Value | Normalized | Type | Notes |
|---|---|---|---|---|
| Resistors 10 | ||||
| ×5 | 2k | 2k | undesignated; read from the schematic by eye | |
| ×4 | 1k | 1k | undesignated (top bus, C2 to ground, Q1 base to ground, Q4 emitter); read from the schematic by eye | |
| ×1 | 360 | 360 | from +12V supply; read from the schematic by eye | |
| ×1 | 8.2k | 8.2k | read from the schematic by eye | |
| ×1 | 3.3M | 3.3M | read from the schematic by eye | |
| ×1 | 18k | 18k | read from the schematic by eye | |
| ×2 | 47k | 47k | signal input and voltage-control input; read from the schematic by eye | |
| ×1 | 47K | 47k | handwritten, frequency trim to Q1 base; read from the schematic by eye | |
| ×1 | 3.9k | 3.9k | emitter tail; read from the schematic by eye | |
| ×1 | 82 | 82 | to -10V; read from the schematic by eye | |
| Capacitors 6 | ||||
| C1 | 0.0047uF | 4.7n | two capacitors both labelled C1; read from the schematic by eye | |
| C2 | 0.0047uF | 4.7n | read from the schematic by eye | |
| ×2 | 150uF | 150u | supply decoupling; read from the schematic by eye | |
| ×1 | 0.1uF | 100n | printed '01µF'; could be .01uF; read from the schematic by eye | |
| ×1 | 10uF | 10u | output; read from the schematic by eye | |
| ×1 | ? | ? | input coupling electrolytic, value number illegible ('µF' only); read from the schematic by eye | |
| Diodes 1 | ||||
| ×8 | 1N4148 | 1N4148 | note: diodes are 1N4148 or equiv; drawn as pairs labelled "R1" and "R2"; read from the schematic by eye | |
| Transistors 4 | ||||
| Q1 | 2N5172 | 2N5172 | handwritten substitute BC547; read from the schematic by eye | |
| Q2 | 2N5172 | 2N5172 | handwritten substitute BC547; read from the schematic by eye | |
| Q3 | 2N5172 | 2N5172 | handwritten substitute BC547; read from the schematic by eye | |
| Q4 | 2N5138 | 2N5138 | handwritten substitute BC557; read from the schematic by eye | |
| Potentiometers 3 | ||||
| Frequency | 25K | 25k | Potentiometer | 'Frequency & Trim' pot, value handwritten; read from the schematic by eye |
| R6 | 1k | 1k | Potentiometer | Q control, handwritten 'lin'; read from the schematic by eye |
| ×1 | 500K | 500k | Potentiometer | handwritten variable resistor in the Vc input, '1V/octave', later note 325K-350K; read from the schematic by eye |
| Switches 1 | ||||
| ×1 | SP3T | SP3T | low-pass / high-pass / bandpass selector; read from the schematic by eye | |